I am making a photo comparison of these two pieces. I could argue that we accept derivations of a standard form of weapons from every culture weapons come from, so why not Native American? I am adding a lot of links about trade pigments and the use of laundry blue to paint artifacts. It is clear that some bluing pigments would have been available from the earliest trade contacts on the northern plains and latter from the mid 19th century synthetic blue and latter other synthetic pigments. I think these pictures show some differences in age and conception. One appears to me as ridged and over done. I feel the one a have shows a more free form. The brass tacks spiral around the wood haft. The whole design is more thoughtful and considered. On close inspection the the two pieces are quite different.
https://www.cac-accr.ca/files/pdf/Vol22_doc4.pdf
http://cool.conservation-us.org/byfo...1999/1328.html
http://www.womenofthefurtrade.com/wst_page18.html
http://www.oldandinteresting.com/laundry-blue.aspx